Electric-current brush structure.



0. E. BECKER.

ELECTRIC CURRENT BRUSH STRUCTURE.

APPLICATION FILED om. 27. i913.

1.@21 ,818. Fatent-ed Apr. 10,1917.

Oil

OLIVER E. BECKER, OF CHICAG,

ILLINOIS.

ELECTRIC-CURRENT BRUSH STRUTURE.

Specification of Letters Patent.

Patented Apr. 10, 1917.

Application filed October 27, 1913. Serial No. 797,469.

To all whom t may concern.'

Be it known that I, OLIVER'E. BECKER, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Electric-Current Brush Structures, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specitication.

My invention relates to those electric current brush structures that include contact elements formed of comminuted material such as carbon or a combination of carbon and copper, etc. It is the main object oi my invention to afford more intimate contact between the contact elements of comininuted material and the conductors that include them in circuit. By means ci' my invention the conducting wire and the means for effecting its electrical connection with the Contact element, frequently the more costly part of the brush structure, may be rcmoved from the contact element when such contact element has been suiiiciently consumed thereafter to be transferred into connection with an unused contact clement. The conducting wire which includes the contact element in circuit is formed of a multiplicity of strands to aiiord flexibility which is particularly desirable at that point where electrical connection is effected between 'the conducting wire and the contact elementu i The end ci the stranded wire which is to have connection with the contact element is ijnovided with a terminal sleeve whose bore is preferably smooth freely to receive the wire and whose exterior is threaded to have engagement with the threads that are formed in a terminal receiving bore which is made in the Contact element. intimate electrical connection is aorded between the stranded wire and its threaded terminal by means of solder which is passed in liquid form into the bore of the terminal sleeve so as to edect extended connection between the wire and terminal sleeve longitudinally of such sleeve. v

I will explain my invention more fully by reference to the accompanying drawing showing one embodiment thereof and in which Figure l is a side elevation, partially in section, of anelectric current brush structure made in accordance with the invention, one form of conducting wire being Yshown in which is indicated electrical connection with the contact element and being broken away owing to the laclr of space for showing its complete length; Fig. 2 is a view of a part of the structure shown in Fig. l, the conducting wire and its threaded terminal being absent; and Fig. 3 is a sectional view on line 3 3 of Fig. l.

Like parts are indicated by similar characters of reference throughout Vthe different figures.

The contact element a is shown as being rectangular in transverse section, though the' invention is not to be limited to suoli a shape. A bore e is formed in that part of the contact element a where electrical connection with the conducting wire cis to be effected. Threads al are formed within the bore I), the extent to which these threads approach the bottom or inner end of the bore varying with the degree of hardness oi the contact element, the threads closely approaching the bottom of the bore in the hardest contact elements and tere minatingnear the outer end of the bore in the case of the softest contact elements and er;n tending varying degrees within the bore according te the degrees of hardness or softness between the hardest and softest materials forming the contact element, such contact element being of comminuted material such as molded carbon, a molded mixture of carbon and copper, f'etc. The conducting wire c is desirably -termed of 'a number of slender strands of copper wire, that end of the conductor c which is to be received within the black a, being placed initially within the bore ci terminal sleeve c, thorough mechanical and electrical connecu tion being aii'orded between the sleeve e and conductor o by means of solder (some of at f) which is applied at the inner end of the sleeve and is caused to flow as far as possible through the bore of the sleeve without issuing from the sleeve at its opposite end. This union between conductor c and sleeve e is effected before the electrical juncture between the sleeve and contact element a. ylhe exterior of the sleeve e is threaded as indicated in Fig. 1 with a thread which corres ends in pitch and size to the thread chasf er tapped in the bore of the Contact@ .nent a, such threads having pitch, shape and diameter according to the size of the contact elementa and conductor c. If the material of the contact element a is comparatively soft the ntti thread al is only started in the bore b, the threads upon the element e forming the remainder of the threads in the bore as the element e is turned to be sucently received inV said bore. it the material or the element a is very hard the threads 0l terminate close to the bottom of the bore b but preferably suthciently short of the bottom of the bore to enable the threaded sleeve e in its turning movements te term a few threads in-the bottom of the here thereby further to assure electrical and mechanical connection between the terminal and contact element. The sleeve e, when driven home, eX- tends a sutlicient distance out of the contact element a to enable it to be grasped by a suitable tool for the purpose of being unscrewed from the element a when such element has been sufficiently consumed, this :feature of construction enabling' me to remove the conductor c and its terminal without applying torsional strain to the conductor so that when the conductor is removed its electrical and mechanical connection with its threaded sleeve terminal is not impaired. l do not limit myself, however, to the projection et the sleeve e beyond the element a as other means may be provided for rotating the sleeve without the aid of the conductor c or if no means are provided for turning the sleeve e the remaining portion of the sutliciently consumed element a may be broken away from the sleeve.

By'means et the threaded engagement between the terminal c and the contact element a; the area ot electrical contact between such terminal and element is not only greatly increased but relative motion between such terminal and element is positively prevented, particularly where the threads of the sleeve form a'part of the .threads al, whereby there is no heating at the place of engagement of the terminal and contact element andno consequent softening of the solder joining said terminal and the naanaie conductor c, these results not only being due to the positive elimination of relative movement between the terminal e and contact element a but also to the greatly amplified area ot contact between the terminal e and contact element a aii'orded by the threads. By means of this construction the consumer needs only to re-supply himself with the contact elements a since the metallic portions c and e may be transferred from consumed contact elements a to new Contact elements with which they may have firm electrical connection as described.

While l have herein shown the threads d in the contact element a of uniform depth and terminating suiiiciently short of the inner end of the bore b to enable the threads in the sleeve e to form a termination of the threads d, ll do not wish to be limited to this formation of the threads al that permits the threads of the element a to take part in the formation of the threads Having thus described my invention I claim as new and desire to secure by Letters Patent the followingz* An electric current brush structure including a contact element having a threaded bore; a conducting wire formed of strands for including said contact element in circuit; and a threaded sleeve whose bore receives one end of the conducting wire and whose threads are greater in extent than the threads in the bore of the contact element whereby the threads of the sleeve complete the formation of the threads in the threaded bore of the contact element as the threaded sleeve is turned home in the contact element.

lin` witness whereof, l hereunto subscribe my name this twenty-fourth day of October A. D., i913.

@LIVER E. BECKER. Witnesses:

lE'rrA L. WHITE, G. L. Censo. 

